Mechanical Measurement and Metrology - Dec 2015

Mechanical Engineering (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) What is Metrology? State any four objectives of metrology.(6 marks) 1 (b) Describe with a neat sketch, International Prototype meter.(6 marks) 1 (c) Discuss the important features of wavelength standard.(4 marks) 1 (d) Build 49.3115mm using M112 set of slip gauges.(4 marks) 2 (a) Define the following terms:
i) Limits ii) Fits iii) Tolerance iv) Deviation.(4 marks) 2 (b) Differentiate between interchangeability and selective assembly.(6 marks) 2 (c) Explain with a sketch, Taylor's principle for design of limit gauges.(6 marks) 2 (d) What is Wear allowance? How it is applied in design of gauges?(4 marks) 3 (a) What are the required characteristics of comparators?(4 marks) 3 (b) With neat sketch, describe the construction and principle of working of sigma comparator.(12 marks) 3 (c) Give the combination of angle gauges to obtain 57° 34' 9'' angle.(4 marks) 4 (a) Illustrate the principle of Interferrometry, with sketches.(6 marks) 4 (b) What is best wire size? Derive an expression for the same.(6 marks) 4 (c) With a sketch, explain the construction of a tool Maker's microscope. What are its applications?(8 marks) 5 (a) What is the significance of measurement system?(4 marks) 5 (b) Define the following terms used with reference to measurement:
i) Accuracy ii) Precision iii) Calibration iv) Threshold v) Sensitivity vi) Hysteresis.(6 marks) 5 (c) Mention any four mechanical and four electrical transducers.(4 marks) 5 (d) Define an error. How errors are classified? Give reasons for each type of error during measurement.(6 marks) 6 (a) Describe in detail a ballast circuit.(8 marks) 6 (b) With a sketch, explain the construction and important parts of a cathode ray oscilloscope.(8 marks) 6 (c) What are the primary functions of a terminating devices?(4 marks) 7 (a) Explain with a sketch, working of proving ring.(6 marks) 7 (b) Explain the working principle of hydraulic dynamometer used for torque measurement.(8 marks) 7 (c) Describe with a neat sketch, McLeod Vacuum gage.(6 marks) 8 (a) What is a Thermocouple? State the laws of thermocouple.(8 marks) 8 (b) Describe the construction and working of optical pyrometer.(8 marks) 8 (c) Write short note on gauge factor.(4 marks)